Radio tuning apparatus



Oct. 25, 1938. A. A. THOMAS 2,134,331

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Patented Oct. 25, 1938 UNITED STATES PATENT OFFICE RADIO TUNING APPARATUS Application June 20, 1929, Serial No. 372,320

16 Claims.

This invention relates to the art of radio reception, and its object is to provide a device of novel construction and improved operation for remotely controlling a radio receiver.

One feature of my invention comprises timecontrolled mechanism for automatically operating a radio receiver at predetermined intervals to tune in a series of selected stations in prearranged sequence. ln this way a diversied radio program lasting many hours is automatically brought in without personal attention.

My novel control device in its preferred form also makes it possible to tune in a desired station at any time by merely pressing a, key or button. This automatic tuning operation is independent of the time-controlled feature and enhances the utility of the invention.

I may also provide a manual tuning key which causes operation of the radio shaft as long as the key is held down, so that the entire dial is swept across the tuning point. When the operator gets the broadcast he wants, he simply leases the key and the station remains tuned in. The key-controlled operations mentioned can not take place as long as the time-control is on, because during that period the keys are automatically locked.

The control mechanism of my invention is housed in a small portable cabinet conveniently located at any distant point from the radio re ceiver. An electric cable containing all the nec-- essary wiring connects the receiver with the control cabinet. A clock in the cabinet controls a series of switches, and these in turn control the operation of an electric motor that drives the tuning shaft. This motor is also controlled by the automatic tuning keys and the manual tuning key carried by the cabinet to bring the radio shaft into the desired tuning position. The cabi net usually has an indicating dial, a volume control knob and a power switch, so that the radio receiver can be fully controlled from a distance in every respect.

The novel features and practical advantages of my invention will be understood from a de scription of the accompanying drawings, in which- Fig. l shows a front view of a control cabinet constructed in accordance with my invention;

Fig. 2 represents a vertical side section on line 2-2 of Fig. 3;

Fig. 3 is a plan view on the broken section line 3-3 of Fi` 2, the clock mechanism bei-ng omitted for clearness;

Fig. 4 is a fragmentary perspective view, partly v (Cl. Z50-40) in section, showing one of the automatic tuning keys and associated mechanism;

Fig. 5 is a fragmentary perspective View of the manual tuning key and certain devices associated therewith;

Fig. 5A shows a fragmentary perspective of one of the motor controlling switches associated with the tuning shaft of the radio receiver;

Fig. 6 represents an inner face view of the switch mechanism associated with the clock in the control cabinet, this view being taken on section line of Fig. 2;

Fig. 6A is an enlarged fragmentary View in section to show certain switch connections controlled by the clock;

Figs. '7, 8 and 9 show structural details of the plug and jack connections surrounding the clock in the cabinet;

Fig. i shows the driving and controlling mechanism associated with the tuning shaft in s ie radio receiver, this View being taken on line ill-iii of Fig. 1l;

Fig. l1 is a side View of the mechanism shown in Fig. l0, looking from right to left;

Fig. l2 shows an enlarged plan view of the connections for operating the tuning shaft by hand, this view being partly a section on line IZ-l?. of Fig. 10;

Fig. i3 is a fragmentary detail view showing one of the motor control switches in closing position, this switch device being the same as that shown in Fig. A;

Fig. le shows a face View of a magnetic clutch member for connecting the tuning shaft with the driving motor, this view being taken on line iii-i4 of Fig. l0; and

Fig. l5 is a diagram of the electric circuit connections that establish certain operative relations between the control cabinet and the tunlng shaft of the radio receiver.

Before taking up a detailed description of the various mechanisms contained in the control cabinet and the radio receiver, I think it will facilitate an understanding of my invention if I first describe in a general way the various oper ations or results obtainable from the control cabinet.

Referring to Fig. l, there is a suitable cabinet C having a front panel l0 from which project various hand-operable members for performing certain operations. A switch lever I2 turns the electric power on or off, this lever operating a main switch of any suitable construction, When this switch is open, all circuit connections for the control cabinet and the radio receiver are cut olf, so that no current is wasted. A knob I3 controls the volume of reproduction in any practical way. By depressing a key I4 the operator connects the tuning shaft with an electric motor which drives the shaft as long as the key is held down. When the operator gets the desired station or broadcast reception, he releases the key and the station remains in tune. At the bottom of the cabinet are five tuning keys I5, which I have differentiated by the suinxes a, b, c, d and e to indicate that they represent certain preselected stations that are automatically tuned in when a control key is actuated. In operating these automatic tuning keys, it is not necessary to hold a key down to get the desired station. The connections are such that an actuated key is locked against return until the selected station is tuned in. Through windows I6 and Il of the front panel are seen respectively a drum I8 which carries wave length or frequency notations, and a drum I9 on which the stations are identified by their call letters. The drums I8 and I9 always rotate in unison and inform the operator which station is on the air and the assigned wave length or frequency of that station.

In the upper portion of cabinet C is a clock whose dial 26 is surrounded by jacks 2| arranged in concentric circles. Each circle of jacks represents a selected station, and in this case there are live circles of jacks because ve stations have been arbitrarily chosen by way of illustration. It has been my experience that almost any locality can get all the desired broadcast programs through a few stations. The jacks 2| are also arranged in radial lines representing hours and half-hours on the clock. Most stations come in on the hour and some on the half-hour. A closer arrangement of jacks to represent quarterhour intervals is hardly necessary. Contact plugs 22 are adapted to be inserted in jacks 2I to tune in a number of selected stations at certain hours in predetermined sequence. For distinction I have marked the different plugs 22 by the suiiX letters a to e. Fig. l shows five plugs inserted in the different circles of jacks 2I to bring in ve successive stations from seven o'clock to eleven oclock. As the hands of the clock move around, the selected stations are automatically tuned in in the order selected, so that a whole evenings, or even a whole days, radio program may be brought in without attention by anybody. The plugs 22 are independently movable and may be inserted in the jacks 2I to bring in any station at any time during the broadcasting period. This automatic time-control of the tuning shaft can be cut out by a switch member 23 when it is desired to use the automatic tuning keys I5, which operate independently of the time control. As long as the time-control switch member 23 is on, the manual tuning key I4 and the automatic tuning keys I are locked against operation. This makes the control cabinet fool-proof and prevents the possibility of disorganizing any part of the interior mechanism.

I shall now describe in detail the mechanism inside the control cabinet C. For this purpose I shall refer mainly to sheets 2, 3 and 4 of the drawings. A bracket 24 is rigidly secured to the back wall 25 on cabinet C by bolts or other fastening members 26 which pass through lateral flanges 2'1 of the bracket. This supporting bracket, which is preferably an aluminum casting, is provided with three hubs or bearings 28, 29 and 30. The bearing 28 supports a rotary shaft 3|, which carries a worm or spiral gear 32 arranged in mesh with a Worm 33 on the driving shaft 34 of a suitable electric motor 35. The latter is rigidly mounted on the bottom plate 36 of cabinet C, as by screws 3`I or otherwise. The bearing or hub 29 supports a shaft 38 which carries a gear sector 39. A link 40 connects the Worm gear 32 with gear sector 39, so that continuous rotation of the worm gear produces oscillating movements of the gear sector. The ends of link 46 are mounted on pins 4I and 42 carried by the gear members 32 and 39 respectively. The gear sector 39 is in mesh with a gear wheel 43 fixed on a rotary shaft 44 which passes through the bearing of bracket 24. The ends of shaft 44 are journalled in suitable bearings 45 secured to the sides 46 of the cabinet. The shaft 44 also carries the indicator drums I8 and I9 previously referred to. The driving connections between the motor shaft 34 and indicator shaft 44 are such that continuous rotation of the motor shaft produces rotation of the indicator shaft for a. half-revolution in alternately opposite directions. The speed of the indicator shaft is preferably about the same as when a radio shaft is tuned by hand. In my own experience, I have found that, in ordinary hand tuning to get a station by ear, it takes about thirty seconds to turn the dial through its full range of movement. The speed of the indicator shaft 44 may vary to suit specie requirements in different designs of control cabinets. In a simpler form of my invention, the indicator drums I8 and I9 may be omitted, together with the electric motor and the associated driving connections. While it is convenient, and perhaps even desirable, to have a station indicator in cabinet C, that is not absolutely essential, because the stations automatically brought in are identified by the circles of jacks 2| and by the tuning keys I5.

The manual tuning key I4 comprises a shank 47 pivoted on a pin 48, which is supported in a sleeve or hollow post 48 projecting from the adjacent side 46 of the cabinet, as best shown in Figs. 2 and 5. A contracting coil spring 49 normally holds the key shank 41 in uppermost position against a suitable stop, which in the present instance is the upper end 50 of the slot 5I through which the key projects out of the cabinet. The upper end of coil spring 49 is connected to a screw-eye 52 secured to the front panel I I) of the cabinet, The key shank 4T has a rear extension 53 and a depending extension 54. The parts 47, 53 and 54 may conveniently be formed as a single member stamped from sheet meta-l, preferably aluminum, which is light and strong. The extension 53 is adapted to be engaged by a catch 55 pivoted on a pin 56, which is supported in a sleeve or bushing 5l projecting from the adjacent side 46 of the cabinet, as clearly shown in Fig. 5. A contracting coil spring 58 normally holds the catch 55 against a fixed stop 59 out of the path of extension 53. One end of spring 58 is secured to catch 55, and the other end is conected to a pin or lug 66 projecting from the side wall of the cabinet. The lower end of the pivoted catch 55 is conected to the magnetic core or plunger 6I of a solenoid coil 62. A convenient way of connecting the members 55 and 6 I is to bifurcate the latter, as indicated at 63 in Fig. 5, to receive the lower end of member 55. A pin 54 pivotally connects the lower end of catch 55 with the solenoid core 6I. The coil 62 is rigidly supported on a suitable block or bracket 65 by means of a strap 66 or otherwise. The block 65 may conveniently be attached to the bottom or side of the cabinet.

It is clear from Figs. 2 and 5 that, when the solenoid 62 is energized, the upper end of catch 55 is rocked over the extension 53, so that the key I4 is positively locked against operation.

Referring to Fig. 5, an insulating block or bracket 61 extending from the cabinet wall 465 carries a pair of switch arms 58 and 69, which may conveniently be secured in slots 'lil of block 6l by a screw or bolt ll. At least one of the switch arms 58 and G9 is of spring metal, which is so positioned that the switch is normally open. When the key I4 is pushed down, the extension 54 rocks rearward and forces the spring arm (i against the arm 59 to close the switch, which remains closed as long as the key is heid down. The function of this switch is to control the electric motor that drives the tuning shaft, as will be explained in due course.

I shall now describe the construction and operation of the automatic tuning keys I5. Since these keys are alike, a detailed description of one is sufficient for all, and for this purpose I shall refer mainly to Figs. 2, 3 and Ll, particularly the latter. Each key I5 comprises a shank I2 formed with a rear extension i3, an upper extension M and a lateral projection 55. All these parts may consist of a single member stamped from sheet metal. The key shanks 'I2 are pivotally mounted on a common shaft or rod l5, which is supported at its ends in suitable brackets 'il secured to the side walls of the cabinet. Each key shank 'I2 has a bushing 'I8 arranged between a pair of fixed collars 'iS on shaft IE, whereby the keys are held against lateral movement while being freely pivoted on the shaft for independent operation. Each key i5 is held in normal uppermost position by a contracting coil spring Sil, which is connected at one end to the shank l and at the other end to a screweye El secured to the front panel of the cabinet. As in the case of the manual key Hl, the keys I5 may be normally held by the coil springs against the upper edges of the slots 82 through which the keys i5 project at the front of the cabinet.

Across the width of cabinet C extend three flat insulating bars 33 and 84, supported at their ends by a pair of slotted blocks or brackets 85. The central bar 83 acts as a spacing strip for the two side bars 85, and these three bars are suitably connected to form a rigid insulating support for a set of switches controlled by `the keys I5. Each of these switches consists of a pair of contact arms 86 and 8'I, which are normally separated to hold the switch open. A convenient way to mount the switch arms in the insulating support 83-84 is to provide each arm with an opening 88 adapted to receive a lateral lug or projection 89 on the adjacent side bar 84, as clearly shown in the perspective view of Fig. 4. In this way, the mere connection of the bars 83-84 automatically clamps the spring arms B6 and 8l rigidly to the support without additional fastening means. Of course, there are other ways of mounting the pairs of switch arms i5-i3? and my invention is not limited to any detail in this respect. The upper extension "I4 of each key I5 is bent forward at I4 to engage the switch arm 85 and move it into contact with the arm 8l' when the key is pushed down. This will be clear from Figs. 2 and 4.

A base plate 9B secured to the bottom of the cabinet carries an insulating bar or block QI below the transverse shaft 16. The block QI is a cornmon support for a series of solenoid coils 92, one for each key I5. As shown in Fig. 4, the coils 92 are set in recesses in block 9| and held in place by straps 93. Each coil 92 has a magnetic core or plunger 94, which is pivotally connected by a pin 95 to a locking pawl or dog 96. A suitable bracket 9'! on base plate 9D carries a pin 98 on which the dog 96 is pivoted. A spring 9S normally holds the locking dog 96 in a forward position out of the path of movement of the transverse lug 'l5 on key I5, so that the latter is free to be actuated. When the solenoid 92 is energized, the core 94 is pulled in until the upper end of dog 95 strikes the transverse lug l5. As long as the coil remains energized, the associated key I5 can not be pushed down. The rear extension i3 of key I5 carries a cross-pin or lateral lug It arranged to be engaged by a locking dog Iil pivoted on a pin |52 which is supported in a suitable bracket H53 fixed on the base plate 95. Each dog I0! has a locking shoulder IM adapted to snap into locking engagement with the cross-pin Iil of the associated key when the latter is pushed down. .A contracting coil spring 55 is connected at one end -to each locking dog Ill, and the other ends of these springs are connected to the iixed insulating support 9|, as indicated at i6@ in Fig. 4. The springs Iil5 normally hold the pivoted dogs IUI against the cross-pins it. When a key i5 is pushed down, the rear pin or lug lili? moves up until it enters the locking recess or shoulder of the associated dog II, which is held forward in locking position by the connected spring This will be clear from Figs. 2 and 4. It should be noted that the locking dogs mi are independently operable, so that the actuation of any key l5 moves only the associated dog into locking position. The purpose of holding an actuated key down is to keep the switch SES-5l closed until the electric motor which operates the tuning shaft has performed its intended function. This will be better understood when I describe the various circuit connections later on. At this point I merely wish to make it plain that when a person operates one of the automatic tuning keys i5, he can remove his finger as soon as the key is down and the associated locking dog lili holds the key in depressed position until the selected station is tuned in.

The individual locking dogs IUI are restored to normal position by a common rod |01 arranged transversely in front of the dogs and supported at its ends in a pair of bellcranks |08 which are pivoted on a cross-bar IDS. The ends of bar IES are held in suitable brackets III) on the sides of the cabinet. Instead of a single supporting bar |09, I may use two separate pins for pivoting the bellcranks |08. One or two springs I I2 connected to the bellcranks IBB hold the latter in a forward position against suitable stops IIS, so that the rod iUI permits forward movement of the locking dogs IUI. The rear arm IM of each bellcrank |08 is pivotally connected to a magnetic core or plungerl II5 arranged to reciprocate in a solenoid coil l I6, which is rigidly supported in any practical way. When the coils IIB are energized, the bellcranks |08 are rocked rearward (clockwise as viewed in Fig. 4) so that the transverse rod ID'I strikes any dog IU! that happens to be in locking position and moves it back to release the depressed key I5, which is instantly raised to normal position by the connected spring 8D. Only one coil IIB is necessary, especially if it be arranged centrally of the restoring rod III'I, and I have shown two restoring coils merely to provide an actuating force at each end of the rod.

A bracket ||1 secured to the top of cabinet C supports a suitable clock K. The dial of this clock is here set into, or made part of, an insulating disk ||8 which iits into an opening H9 in front panel |0 of the cabinet. Screws |20, or other fastening means, hold the disk |I8 rigidly in place. The disk H8, which is preferably molded of suitable insulating material, such as Bakelite, carries the jacks 2| previously referred to in connection with Fig. l. The construction of these jacks is best shown in the enlarged views of Figs. '1, 8 and 9. Since the jacks 2| are alike, it is only necessary to describe one of them. Each jack comprises a sheet metal sleeve or thimble I2! set rmly in an opening |22 of disk H8. The sleeves i of each circle of jacks are rmly connected to a sheet metal ring |23, which is provided with properly spaced openings |24 surrounded each by a short cylindrical flange or bushing |25. When the sleeves l2! are inserted into the openings |24 of ring |23, the flanges grip the sleeves in a tight rit, and not only hold them rrnly in place but also connect them in good electrical Contact with the ring. The sleeves 12| and ring |23 should be made of good conducting metal, like brass. The plugs 22 co r.- prise a cylindrical metal shank |23 adapted to t snugly in the sleeves or thirnbles |22, which may be provided with a spring tongue |21 arranged to snap into a circular groove |28 in shank whereby the plug is held in fully inserted position and remains in good electrical Contact with sleeve ll. The latter may be inserted into the holes |22 of disk |18 ar'ter the same has been molded, or the sleeves may be mounted on the concentric rings |23 before the composition material is poured into the mold. There are doubtless other ways of mounting and connecting the lacks 2|. and the ular construction just described is to be considered merely by way of example.

The insulating disk |58 carries on its inner face a series of spring contact strips |29 arranged over the rear openings 530 in disk H8. In other words, the radial spring strips or ngers 29 are in line with the radial rows or" jacks 2l appearing on the front panel l0 of the cabinet. The contact lingers |22 are secured to disk H8 in any practical way, as by screws |3i. When a plug 22 is fully inserted in a jack, the projecting end 32 (see 8) pushes the adjacent spring 'linger |29 slightly to the rear, so that a rm pressure contact is established between those two parts. The contact lingers |29 are engaged by a conducting arm |33 xed on the hollow shaft E34 that carries the hour hand |35, as best shown in Fig. 6A. The rotary arm |33 is always in electrical contact with a lined plate carried by the insulating disk H8. Ir" desired, a small spring blade i3? may be attached to the arm |33 to maintain good electrical contact with plate "M A rod or stit wire |38 is con- 10b'. nected at one end to plate |35 and at the other end to a circuit lead |39. The conductor |38 may be placed in a radial groove in disk |58, so as to be out of the way oi arm |33, if that should be found necessary.

It will be clear from the preceding paragraph that the Contact arm |33 is in effect a rotary terminal of the circuit lead |35, so that the radial ingers |29 are successively connected to conductor |33 as the hour hand of the clock moves around. The contact arm |33 and hour hand 35 are always in radial alignment and move as a unit. The number of minutes during which the arm |33 remains in contact with a jack strip |29 depends upon the width of the contact area and that can be regulated as required. The contact between members |29 and |33 need only be long enough to allow the electric motor to rotate the radio shaft into tuning position, and that tak-es only a fraction of a minute. The disk ||8 is formed with a recess |40 in which the dial 20 is located and which allows space for the hands of the clock. The recess |40 is closed by a sheet metal cover |4|, which ts into the recess and is removable or swings open to permit access to the hands and for Winding the clock. It is evident that the minute hand of the clock may be used in conjunction with the hour hand to close the circuit through an inserted plug on the exact minute. This will be understood without additional illustration. In the broad aspect of my invention, any other practical time-.controlled switch connections may be employed.

Referring to Figs. 2 and 3, the bracket or casting 24 carries a pin |42 on which an insulating arm |43 is pivoted. This arm is provided with a pair of metal plates or extensions |44 and |45, which may conveniently be attached by screws |45. An insulating bracket |41 secured to casting 24 carries a contact button |48 arranged to be normally out of engagement with plate |44. Another insulating bracket |49 on casting 24 carries a contact button |50, which is normally engaged by the plate or metal extension of the pivoted arm |43. A coil spring |5| connected to arm |43 normally holds the plate |45 in rm pressure contact with button |50, while the switch members |44 and |48 are kept apart. The piv oted arm |43 carries an armature |52 in operative relation to an electromagnet or solenoid |53, which is supported on a suitable bracket |54 on the casting 24. When the electromagnet |53 is energized, the armature |52 is attracted and the switch arm |43 is rocked clockwise (as viewed in Fig. 2) to close the switch contacts |44--I48 and at the same time open the contacts |45-|50. The circuit connections of these switches will be subsequently explained in detail, but I may say here that the closing of switch contacts |44|48 closes the circuit of solenoids ||6 to operate the key-restoring bar |01, while the opening of switch |45|5 breaks the motor circuit and stops the tuning shaft.

Referring again to Fig. 3, the finger pieces |2 and 23, which are shown as toggle levers, are parts of suitable switch devices indicated diagrammatically by the rectangular outlines |55 and |56, which may be considered as representing the casings in which the switch parts are housed. It will not be necessary to show the structural details of switch 55, because any kind of on-and-oi switch will do. As for the switch operated by finger piece 23, I shall explain that in connection with Fig. l5. The rotary knob |3 is supposed to operate any suitable device |51 for controlling the volume of reproduction. The structural details and electrical connections of a volume Controlling device need not be shown or described, because they form no part of this invention, and are readily understood by those skilled in the art. There are various ways of controlling the volume of a radio loudspeaker, and it is suliicient to say that the device |51, which is controlled by knob |3, is operatively connected with the radio receiver to regulate the volume of reproduction.

I now come to the mechanism mounted in the radio receiver cabinetl for operating the tuning shaft. This mechanism is illustrated on sheets ll O r frame |55 5 and 6 of the drawings, and certain details are also shown in the perspective view of Fig. 5A. The cabinet containing the radio receiver and associated mechanism is conventionally shown as a rectangular box R of suitable dimensions and design. Of the apparatus necessary for radio reception, no illustration or description is necessary, because we are here concerned. only with the operation of the rotary shaft |58 on which the tuning condensers |59 are mounted. These condensers may be of any suitable construction to permit the regulation of capacity by rotation of shaft |58 in either direction. The back wall |89 of cabinet R carries a casting I6| secured by bolts |52 or otherwise. Referring to Fig. 10, it is seen that the casting I6I has a right-angled arm |93 which terminates in a bearing |64 for one end of the condenser shaft |58. The other end of this shaft is supported in a suitable bearing |65.

The supporting frame or casting |6I is provided with three bushings |58, |51 and |68. A worm or spiral gear |69 is rotatably supported in bushing |85 and is permanently in mesh with a worm |19 on the drive shaft I1| of an electric motor |12, which is suitably mounted on the bottom plate |13 of the radio cabinet. The hub or bushing |81 of frame |8| supports a rotary gear sector |19', which is operatively connected to the worm gear |99 by a link |15. The ends of this link are pivotally connected to pins |18 and |11 carried by the gear members |69 and |14 respectively. The gear sector |14 is in mesh with a gear wheel |18 fixed on a shaft |19, which is journailed in the upper hub |68 of the supporting By comparing Figs. 2 and 11, it will be observed that the driving connections between the electric motor and the dial shaft 44 in Fig. 2 are the same as the driving connections between the electric motor |12 and shaft |19 in Fig. ll.. Therefore, when the two electric motors are energized, the shafts 44 and |19 are rotated in unison at the same speed. It is assumed that either the loads on the two motors are substantially the same, or that the motor having the lighter load receives correspondingly less current, as regulated by an ordinary rheostat. For example, the indicator shaft 44 in the remote Control box may carry a brake or other artificial load to equal the load on the tuning motor |12 in the radio cabinet. As every electrical engineer knows, synchronizing devices for electric motors are old and well understood, so I need only repeat that any suitable means may be employed to produce synchronous movement of the motordriven shafts 88 and |19. In this instance it has been assumed that the tuning shaft |58 of the radio receiver encompasses the entire broadcasting field by rotation of half a revolution. For this reason the shafts 44 and |19 oscillate back and forth through a radius of 180 degrees, While the gear wheels 32 and |99 are driven continuously in the same direction at properly reduced speed. This automatic reversal of operation of shafts 44 and |19 is accomplished by means of the connecting links 49 and |15 and their respective gear sectors 89 and |14. Y

Referring to Fig. i0, the inner end of shaft |19 carries a magnetic clutch disk |89 of suitable construction. In this case the isk |89 has pole pieces I8I which carry magnetizing coils |82, as best shown in Fig. 14.-. The electric current is led through these coils by means of a pair of insulated contact rings |83, which Aare constantly engaged by a pair of brushes or other contact members |84. These brushes may conveniently be mounted on an insulating block or extension |85 secured to the main frame I6I. The right end of condenser shaft |58 carries a magnetic armature disk |88, which is slidably mounted on the shaft by means of a key |81. It is seen in Fig. 10 that the shafts |58 and |19 are substantially in axial alignment and are normally disconnected. This permits the tuning shaft |58 to be operated by hand in the usual way. When the clutch coils |82 are energized, the slidable armature disk |88 is instantly attracted to the pole pieces |8| and held with such force to the polar faces that the shafts |58 and |19 become coupled to operate as a single member. When the circuit of the clutch coils |82 is interrupted, the armature disk |86 is immediately released and the tuning shaft |58 becomes disconnected from the clutch shaft |19. If desired, a retracting spring may be inserted for the armature disk |86, but as a rule that is not necessary, because the armature moves away sufficiently from the demagnetized pole pieces |8| to cause uncoupling of shaft |58 from shaft |19.

Referring to Figs. 11 and 12, the front panel |88 of radio cabinet R carries a hand knob |89 for operating a shaft |99, which is provided at its inner end with a bevel pinion |9| arranged in mesh with a second bevel pinion |92 fixed on a shaft |93. A bracket |94 is provided with a bearing |95 for shaft |98 and with a bearing |96 for shaft |93. The tuning shaft |58 carries an indicator drum |91, which is supposed to be a duplicate of the indicator drums i8 and I9 in control cabinet C. All these drums may conveniently be cast of aluminum on account of its lightness, or they may be shaped from sheet metal, like brass, and marked on the periphery with appropriate notations. The indicator drum |91 carries an internal gear |98, which meshes with a pinion |99 on shaft |93. By means of the connections above described, the tuning shaft |58 and drum |91 can be operated manually at reduced speed by turning the knob |89 in one direction or the other. The markings on drum |91 are visible through a sight opening 289 in the front panel I 88 of the radio cabinet. It should be noted that the manual driving connections do not interfere with the operation of the tuning shaft by the electric motor |12. The manual operation of tuning shaft |58 is not absolutely necessary, because the electric motor |12 can always be used. In that case it is only necessary to provide the radio cabinet with a manual tuning key, like the key I4 on the remote control cabinet C, to control the circuit of the driving motor. When the hand operation of the radio shaft is dispensed with, the magnetic clutch I89-I88 is not necessary, because in that case the tuning shaft can be permanently coupled to the motor. If the tuning knob |89 is used for turning the condenser shaft 58 by hand, independently of motor |12, the clutch |89 is preferably inserted between the gear |69, and the motor shaft, so that the relation of the tuning shaft and the automatic reversing mechanism remains fixed. This will be clear to any mechanic.

Referring to Figs. 10 and 13, the tuning shaft |58 carries a series of disks 29|, which are alike in structure and which I have differentiated by the suffix letters a to e, respectively, to indicate that each disk represents a certain selected station. These disks are preferably cast or molded of insulating material, such as Bakelite, and they are held in spaced relation on shaft |58 by integral hubs 202, which are secured to the shaft by pins 203 or otherwise. Each disk 201 is provided with a contact piece 204 extending axially across the periphery of the disk and arranged in predetermined radial position, in accordance with the station represented by the disk. The contact pieces 204 may be rigidly xed to the disks 201, as by being molded 1n place, but I prefer to mount them in such a way that their radial position can be adjusted for any station on the dial. As best shown in 13, the peripheral contact 204 is an integral lateral extension of a spring arm 205 which has an annular washer-like enlargement 205 tting over the hub 202 of the disk and held in place by the pin 203. The adjacent face of disk 201 is formed with radial grooves or corrugations 20'! adapted to receive a radial rib 208 on the spring arm 205. The normal tension of arm 205 holds the rib 208 in rm frictional locking contact with the grooved face 20'1 of disk 201 in any position to which the arm 205 may be adjusted. This frictional locking contact, however, is sufficiently yieldable to permit radial adjustment of the contact arm 205 relative to the disk. For this purpose the arm 205 has a lateral lug 209 which may be struck up as an integral extension of the arm. By inserting a suitable instrument into the cabinet to engage the lug 209, the tuning shaft may be turned by hand to move the disk 201 while the contact arm 205 is held stationary. In this way it is a simple matter to adjust the radial position of any conta-ct 204 on its supporting disk 201.

Each disk has associated with it a pair of insulated switch arms 210 mounted on a block 21 I which may be molded of insulating material. The supporting blocks 21 1 are pivoted individually on a common shaft 212 and held spaced by bushings 213. The ends of shaft 212 are supported in side brackets 214, which are rigidly connected at the top and bottom by cross pieces 215 and 215 to form a unitary supporting frame for the series of switches 210 and the associated actuating mechanism. The bracket 154, which supports the shafts 100 and 193, as I have previously mentioned, may conveniently be attached to the bottom plate 215. A convenient way of securing the framework 214-215 in the cabinet is to provide the base plate 216 with a fla-nge 211 adapted to receive suitable fastening members 218 for attaching the frame to the inner wall of the front panel 188. This is clear from Figs. 5A and 11. The unitary mounting of all the switches 210 and their associated actuating mechanism makes it possible to assemble the parts completely before inserting the frame 214-216 into the radio cabinet.

The base plate 216 supports a series of electromagnets or solenoids 218, which I have differentiated in Figs. 10 and 15 by the suiiix letters a-e as a convenient way to indicate that they are associated, respectively, with the tuning disks 20m-201e. Each block 211 carries an armature 219 adapted to be attracted by the electromagnet 218 when the same is energized. A coil spring 220 normally holds each pivoted block 211 in the position shown in Fig. ll-that is, with the rear portion of the block raised so that the switch arms 210 are out of contact with the associated disk 201. A fixed rod 221 supported between the side brackets 214 acts as a common stop for the pivoted blocks 211 under the action of springs 220. When an electromagnet 218 is energized, the associated block 21 1 is rocked into the position shown in Fig. 13 to hold the switch arms 210 in pressure contact with disk 201. As soon as the electromagnet is de-cnergized, the spring 220 quickly moves the block 211 into the position shown in Fig. 11.

Referring to Figs. 5A, 11 and 13, each pivoted block 2H also carries a switch arm 222, which may simply be a strip of spring brass inserted at one end in a slot in the block, as best shown in 13. The cross-bar 215 carries a series of insulated contact buttons 223 arranged to be engaged by the switch arms 222 when the blocks 211 are actuated into circuit-closing position, as shown in Fig. 13. When the blocks 211 are in normal position, as illustrated in Fig. 11, the movable switch arms 222 are separated from the fixed contacts 223. Since each switch arm 222 and its associated contact 223 constitute a switch, I have indicated this series of switches in the circuit diagram of Fig. 15 by the reference numeral 223 with the suffixes a-e for distinction, That makes it easier to trace the circuits.

In the iirst part of this speciiication, I have stated that the iinger piece 23 on the front panel 10 of the remote control cabinet C operates a switch device to throw the time mechanism into and out of operation. A simple form of switch controlled by the finger piece 23 is shown diagrammatically in Fig. l5. The hand member 23 is connected to a cylinder or drum 224, which is pivoted on a shaft indicated by the dotted line 225. The drum 224 has a lug or extension 226 arranged between a pair of xed stops 22T and 228. A contracting coil spring 229 connected to the drum above its pivot is so arranged as to hold the lug 22S against the off stop 221 or the on stop 228. The switch drum 224 controls two switches indicated diagrammatically by two pairs of contact arms 230 and 231. In the actual device, these switch arms would be arranged side-by-side, but in the diagrammatic drawing of Fig. 15 I have displaced them laterally. For this reason it was necessary to represent the drum 224 in two sections connected by the dotted axial line 225. The toggle drum 224 is provided with a projection 232. When the toggle lever 23 is in oiT" position, as shown in Fig. 15, the switches 230 and 231 are open, it being assumed that the switch arms are normally held open by inherent tension. When the finger piece 23 is thrown to the right (as viewed in Fig. 151, the projection 232 moves the lower switch arms 230 and 231 into contact with the upper arms and thereby closes both switches.

I shall now describe the circuit connections in Fig. 15. A switch plug 233 adapted to be inserted in an ordinary house-lighting socket is connected to a pair of mains 234 and 235. The switch operated by the toggle lever 12 is` inserted in conductor 235, although it may obviously be placed at any other point for opening and closing all circuits. The electric motors 35 and 1'12 are connected at one side to the circuit lead 235 by wires 23S and 231. The other side of each motor is connected to a wire 238 which leads to the switch arm 68. I might explain here that I use the word wire in this description as a convenient term to include any kind of electrical conductor, without regard to form, shape, or material, provided only it is practical to use. A wire 239 connects the switch arm 60 to the main conductor 234. It is clear from this that the motors 35 and 112 are connected to the power circuit in parallel through switch 158-69. When this switch is closed by the manual tuning key 14,

the two motors are driven synchronously to operate the indicator shaft 44 in the control cabinet C and the tuning shaft |58 in the radio receiver. The circuit of clutch |38 is closed through wires 240 and 24|, which are connected to the switch arms |84. The clutch circuit, like the motor circuits, is closed through the key-operated switch 68-69.

The switch contacts 2Min-2me are connected in parallel to a pair of conductors 242 and 243. Conductor 242 is connected at 244 to the main lead 235, while conductor 243 is connected to a wire 245 which leads to one side of the solenoid |53. The other side of this solenoid is connected by a wire 24S to the circuit main 234 at point 241. rBhe switch contacts |48 and |58 associated with solenoid |53 are connected to conductor 234 by wires 248 and 249. The contact plate E44 is connected by wire 258 to a conductor 25| which leads to one side of the two solenoids H6. The other side of each solenoid is connected to a conductor 252, which in turn is connected at 253 to a wire 254 leading from the circuit main 235. The solenoids |18 are therefore connected in parallel to the power circuit through switch hid-|48 The switch plate |45 carried by the pivoted arm |43 of solenoid |53 is connected to a conductor 255 from which parallel branch lines numbered consecutively 256 to 268 lead respectively to the movable or lower contact arms of the five switches 223e 223e. The upper or Stationary contacts of these ve switches are connected by parallel branches marked consecutively 26| to 255 to a common conductor 256, which is connected at 261 to conductor 238. the switches 22M- 223e are connected to the power circuit in parallel through switch contacts M15-|58, which is under the control of solenoid |53. The solenoids 2|8a-2|8e, which control the associated switches 2 0a-2|8e, are connected at one side in parallel to a conductor 268, which is connected at 265 to the circuit lead 234. The other sides oi the solenoids 2|8a-2I8e are connected by separate Wires marked 210-214 to ve conductors marked 215-219- One contact arm of each of the switches BSc-86e is connected to the common conductor 254, while the other contact arms of these switches are connected respectively to conductors 21B-215, 21|-216, 212-221, 223-228 and 214-219. The dash mark in the last sentence signies that each pair of conductors is electrically connected to form in effect a single conductor.

In Fig. 15 I have distinguished the rive circles oi jacks 2| by the suix letters awe, so that the outer circle of jacks shall be called 2id, the next circle 2lb, and 'so on. The connecting rings |23 have also been distinguished by sufhx letters c-c, and these circles have been shown in the form of lines to represent diagrammatically wire connections. It will thus be clear that the jacks 2id of the outer circle are electrically connected by a wire |23a, the jacks 2lb of the next circle are connected by a wire |235, and so on for the other circles of jacks.- The five connecting wires |23cL--i23e are connected respectively to conductors 215, 215, 212, 213 and 218. The conductor |33, which is connected to the rotary switch arm E33 of the clock, leads to one of the switch contacts 23E. The other contact of this switch is connected by a wire 285 to the circuit main 235. The lower contact arm of switch 238 is connected by wire 23| to one side of the solenoid 62, the other side of which is connected by wire 282 to This means that the circuit lead 235. The upper Contact arm of switch 230 is connected by wire 283 to a conductor 284, which serves as a common connection for one side oi the solenoids Q2u-92e. The other side of these solenoids is connected to a conductor 285 which leads to the circuit main 234. In other words, the solenoids 32a-92e are connected in parallel to conductors 284 and 285, and the circuit of these solenoids can bev closed only through switch 230 and solenoid 62.

Let us now assume that the time switch 224 is closed and that ve plugs 22 have been inserted in the positions marked 22a-22e in Fig. l5. We shall further suppose that the hands of the clock indicate the hour of seven, which means that the rotary switch arm |33 is in contact with the radial strip |29 which is in line with the hour hand at this time. The plug 22e closes the circuit of solenoid 2|8e through the following connections: Circuit main 234 to point 283, wire 268, coil of solenoid 218e, wires 214 and 213, contact ring |238, through inserted plug 22e to radial strip |23, switch arm |33, wire |33, closed switch 23|, wire 288, and return lead 235. When the solenoid 2|8e is energized', it rocks the associated block 2|| (see Fig. 13) and throws the switch arms 2| 8e into contact with tuning disk 23|c. This movement of block 2| closes switch 223e, whereby the motor circuits are closed through the following connections: Circuit lead 234, wire through closed switch contacts ISB-445, conductors 255 and 268, across the closed switch contacts 223e, wires 265 and 255 to point 251 of conductor 238. From there the circuit divides in parallel, one branch going through motor 35 and wire 238 to the return main 235, and the other branch going through motor |12 and wire 23? to the return main. At the same time, the circuit is closed through the coils of clutch |85 through wire 24E, contact brushes |84, and wire 248. Consequently, the two electric motors operate simultaneously at the same speed and the clutch disk |36 is in coupling position, so that the tuning shaft |58 is operated by motor |12. At the same time, the motor 35 inthe control cabinet C operates the indicator drums i8 and I9 in synchronism with the indicator drum |91 of the radio receiver.

In addition to the closing of the various circuits above described, the solenoid 52 and the five solenoids Q2u-92e are energized to lock the manual tuning key |4 and the automatic tuning keys I5 against operation. These Asix solenoids are energized through circuit lead 234, conductor 285, solenoids Q2u-32e in parallel, conductors 284 and 283, through the closed switch 235, conductor 28|, through solenoid 82, and by wire 282 to the return lead 235. The energized solenoid 52 rocks the dog or latch 55 into locking position against the rear end of key |4, and the energized solenoids Q2u- 92e move the latches 33 against the lateral lugs 15 of the automatic tuning keys I5, which are differentiated in Fig. l5 by the suniX letters ab-c Therefore, as long as the time-controlled mechanism is in operation, it is impossible to push down the keys I4 and l5.

The circuits of the electric motors 35 and |12 and the solenoid 2|3e remain closed until the contact piece 204 on the rotating disk 20| e bridges the switch arms 2| 5c. When that occurs the circuit of solenoid |53 is closed as follows: From circuit lead 234 to point 241, wire 246, through solenoid |53, wires 245 and 243, across the connected switch arms 2|8e to return lead 235. When the solenoid |53 is energized, it rocks the arm 143 and opens the two switch contacts 145-155. This breaks the motor and clutch circuits, so that the radio shaft 58 is automatically stopped in correct tuning position. rIhe circuit through solenoid 218e is opened when the clock-driven switch arm 133 moves out of contact with the radial strip 129. When the energized solenoid 153 rocks the arm 14S to open the various circuits mentioned, it closes the switch contacts 144 and 148 to energize the solenoids 115, which operate the restoring rod 15V. Since, however, no tuning key 15 was actuated, this movement of rod 10'1 is an idle one.'

The circuit connections that have been described or plug 22e are the same for the other four plugs 22a 22d, except that each particular plug closes the circuit through a corresponding solenoid 2i8a-218d. For instance, at eight oclock the rotary switch arm 133 cooperates with plug 22e to close the circuit through solenoid 2i8c, whereupon the contact arms 21de are thrown against the associated tuning disk 251e and the switch 223e is closed to complete the motor and clutch circuits in the manner already described. It will not be necessary to repeat in detail the circuit connections for solenoid Elfic, because they are evident from Fig. 15. At nine oclock, solenoid 21817; at ten oclock, the solenoid 218d is energized; and at eleven ociock, the circuit is closed through solenoid 218s. Since the contact piece 204 in each tuning disk 2.111 is inserted in tuning; position for a particular station, the radio shaft automatically stops in tuning position when a pair of actuated switch arms Mea- 219e is bridged by the contact piece. 204 of the associated disk. I might explain here that in Fig. 15 I have purposely shown the contact pieces 254 as mere inserts in the periphery of the disks, it being understood that these contact pieces may be circumferentially adjustable, as previously explained in detail.

It is clear from the preceding description that a person can provide himself with an entire evenings (or a whole days) program of selected radio reception by the simple expedient of inserting the plugs 22 in the appropriate jacks. This operation is so simple that a child can do it. Since city newspapers publish daily complete radio programs, a person can make his selections every morning, afternoon or evening to bring in automatically the desired stations in predetermined sequence. If one station is to be repeated at a later interval, it is only necessary to insert a second plug in the same circle of jacks. The front panel 10 of the control cabinet C should be appropriately marked to indicate the stations represented by the circles of jacks, as for example, as shown on Fig. l, the station call-letters WEAF, WJZ, etc., have been applied to the respective circles of jacks. Call letters of other stations that may be more desirable to the listener may be inscribed in place oi those shown, or else station wave lengths may be employed. The control cabinet can be made as ornamental as desired, and it may be put in any convenient place, as on a mantel, shelf, table, desk, chair, or where not. Incidentally, the cabinet performs the additional function of a clock.

When the time-controlled mechanism is not wanted, the toggle lever 23 is thrown into ori position, as shown in Fig. l, whereby the keys 14 and 15 are released for operation because the the inserted plug 22h energizes solenoids 62 and Q2u-92e are de-energized by the opening of switch 233. The key 14 is held down until the desired station is tuned in. When this key is operated, the motor and clutch circuits are closed as follows: From the main lead 234, wire 239, through closed switch contacts E9 and S8, wire 238, through the windings of electric motors 35 and 1'12 in parallel, and from there through wires 236 and 231 to the return lead 235. At the same time the circuit of clutch 180 is closed through wires 233, 241 and 240, as previously described. As soon as the desired station is tuned in, the key 14 is released, whereupon the switch contacts 68-89 are instantly opened to break the motor circuit and stop the radio shaft in tuning position. In receivers of the present day, it is not necessary to adjust the tuning shaft with microscopic accuracy, because a certain amount of broad tuning is not only permissible but actually desirable lor better reproduction. Therefore, when a person holding down key 14 hears the broadcast reception that he wants, he simply releases the key.

The automatic tuning keys 15 in this instance represent the same five' stations as the ve circles of jacks 21 of the time-controlled mechanism, but it is evident that they may represent ve other stations. In that case, however, it will be necessary to have ve additional tuning disks 201 for those other' stations. The purpose of the tuning keys 15 is to enable a person to bring in a desired station without regard to time. Referring to Fig. 15, let us say that the key 15a is actuated to bring in the station represented by that key. When the switch contacts 85a are closed by key 15a, the circuit of solenoid 218a is closed as follows: From main lead 234 to point 259, wire 268, solenoid 218a, wire 210, through closed switch contacts 85a, and from there through wire 254 to the return lead 235. When solenoid 218a is energized, it operates in the manner previously described to move the switch arms 211la against the tuning disk 291er and at the same time close the switch contacts 223a. The closing of switch contacts 223@ cuts the electric motors 35 and 112 into circuit, while at the same time closing the circuit of clutch 180. The motor and clutch circuits are interrupted when the contact piece 204 of disk 201er spans the switch arms 213e, as above described in connection with the clock-controlled mechanism. When any one of the other keys 15b-15e is actuated, the circuit is closed through the corresponding solenoid 21819-4186. These circuit connections need not be described, because they are easily traced in Fig. 15. It is therefore clear that the tuning connections associated with the radio shaft 158 are independently controlled by the clock mechanism through plugs 22 and by the selective keys 15.

When a tuning key 15 is actuated, tbe

associ.- ated latch 101 snaps into locking engagement with the rear end of the key and holds it down even when the key is released. When the solenoid 153 is energized on the opening of the motor and clutch circuits, as previously explained, the normally open switch contacts 144 and 148 are closed to energize the solenoids 115, whereupon the shaft 101 is rocked rearward to throw the actuated latch 101 back to normal releasing position. The previously depressed key 15 is therefore automatically restored to normal position after the desired station has been tuned in. Before leaving Fig. 15, I might explain that the dotted line D indicates diagrammatically the separation of the control cabinet from the receiverthat is, what is above the line D is in the receiver cabinet, and what is below the line is in the remote control cabinet. The wires crossing line D are supposed to be an electric cable connecting the two cabinets. Of course, the control cabinet could be mounted on the radio cabinet, or even made a part thereof, but I prefer to have the control cabinet separate, so it can be moved about to any convenient place.

Although I have shown and described certain specific mechanisms, I want it understood that my invention is not limited to the details set forth. I realize that the basic features of my automatic tuning apparatus may be mechanically embodied in various forms without departing from the scope of the invention as defined in the appended claims. Furthermore, it is evident that some features of this invention may be used without others.

I claim as my invention:

1. The combination of a radio tuning shaft, mechanism for actuating said shaft to a plurality of diiferent positions to tune in certain stations, clock-controlled connections for energizing said actuating mechanism at predetermined intervals, key-controlled connections for energizing said actuating mechanism independently of said clockcontrolled connections, and means for preventing operation of said key-controlled connections when the clock-controlled connections are in operative condition.

2. A tuning unit operable at a distance from a radio receiver and adapted to be electrically connected therewith, said unit comprising a set of clock-controlled switches for causing operation `of the tuning shaft at predetermined intervals to tune in one or more selected stations, a separate set of manually operated switches in said unit each for tuning in a desired station independently of said clock-controlled switches, and means for preventing operation of either one of said sets of switches when the other set is used.

3. The combination of a radio tuning shaft, an electric motor for operating the same, a series of contacts mounted on said shaft in predetermined angular relation, a pair of spaced members constituting a normally open switch associated with each contact, said switches being mounted to have independent movement and normally held out of the path of said contacts, an electromagnetic device for controlling the position of each switch, electrical connections for closing the motor circuit to actuate said shaft, selectively controlled mechanism for energizing any one of said devices to move the associated switch into the path of the adjacent contact, and means whereby the motor circuit is automatically broken when the spaced members of the actuated switch are bridged by the associated contact.

4. The combination of a radio tuning shaft, an electric motor for operating said shaft, a series of contacts mounted on said shaft in predetermined angular relation, a pair of spaced members constituting a normally open switch associated with each contact, said switches being mounted to have independent movement and normally held out of the path of said contacts, an electromagnetic device for controlling each switch, electrical connections for closing the motor circuit to actuate said shaft, time-controlled mechanism for actuating a plurality of said devices at different intervals to move the associated switches into the path of their respective contacts, means whereby the motor circuit is automatically broken when the spaced members of an actuated switch are bridged by the associated contact, and manually operable connections associated with said mechanism for predetermining the time and sequence of operation of said switches, so that a plurality of selected stations are automatically tuned in at the desired intervals.

5. The combination of a radio tuning shaft, means associated with said shaft for stopping the same in any one of a` plurality of predetermined tuning positions, time-controlled mechanism for operating said means at predetermined moments, key-controlled connections for operating said means independently of said timecontrolled mechanism, and means for preventing actuation of the key-controlled connections while the time-controlled mechanism is in operation.

6. The combination of a. radio tuning device, means associated with said tuning device for adjusting the same to any one of a plurality of predetermined tuning positions, time-controlled mechanism for operating said means at predetermined moments, key-controlled mechanism and connections therefor for operating said means independently of said time-controlled mechanism, means for preventing actuation of the key-controlled mechanism while the timecontrolled mechanism is in operation, and switch means operative at will which in one position renders effective only the time-controlled mechanism and in the other position renders effective only the key-controlled mechanism.

7. In radio tuning apparatus, the combination of a plurality of devices representing certain stations, tuning mechanism controlled by said devices, time-controlled means for energizing one or more of said devices at predetermined intervals, manually operable means for selecting the devices to be energized, manually controlled Switches for selectively energizing said devices independently of said time-controlled means, and means for preventing operation of said switches when said devices are under the control of said time-controlled means.

8. In a radio receiver, a tuning shaft carrying an insulating disk, a contact member supported on said disk for movement therewith and circumferentially adjustable thereon, said member having a resilient portion, means on said disk arranged to be engaged by said resilient portion which presses against said means for frictionally holding the contact member in adjusted position to represent a selected station, a normally open switch adapted to be closed by said member, and means controlled by said switch for automatically stopping said shaft in tuning position for the station represented by said member.

9. The combination of a radio receiver having a tuning shaft rotatable in opposite directions through a predetermined arc, an electric motor for operating said shaft, means for automatically reversing the rotation of said shaft at each end of its arc of travel, a box located at a distance from said receiver and operatively connected thereto by electric conductors, a set of keys carried by Said box and representing each a certain station, switch means controlled by each key for closing a circuit to energize said motor and operate said shaft, electromagnetic means controlled by an actuated key to automatically stop said shaft in tuning position for the station represented by said key, a separate key on said box, a circuit different from the first mentioned motor circuit directly connected to the motor, and switch means controlled by said separate key for continuously energizing said last mentioned motor circuit whereby the tuning shaft will be actuated without interruption in either direction so long as said separate key is maintained in operative position.

10. In radio tuning apparatus, the combination of a rotary tuning shaft, an electric motor for operating said shaft, a plurality of contacts, insulated from each other and from the shaft, rotatable with said shaft and so positioned. as to represent certain stations, a normally open switch device associated with each contact and adjustably mounted to move into and out of the path of said contact, means for normally holding each switch device out of the path of the associated contact, selectively operable means for moving any switch device into the path of the associated contact, and circuit connections for stopping said motor when one of said contacts engages the associated switch device.

11. In radio tuning apparatus, the combination of a rotary tuning shaft carrying a plurality of insulating disks, means for operating said shaft, a contact carried by each disk in predetermined position to represent a selected station, a pair of insulated switch members associated with each disk and adjustably mounted to move into and out of engagement with said disk means for normally holding each pair of switch members away from the associated disk, selectively operable means for moving any pair of switch members to engage the associated disk and the contact carried thereby, and connections whereby said shaft automatically stops in selected tuning position when a pair of said switch members engages the associated contact.

12. As a new article of manufacture, a remote control box having means for electrically connecting it with a radio receiver and containing a clock, a plurality of switches selectively controlled by said clock for causing one or more stations to be automatically tuned in at predetermined intervals, a plurality of station-selecting keys carried by said box and manually operable independently of the clock to bring in a desired station at any time, and means for preventing operation of said station-selecting keys when the switches are under the control of the clock.

13. As a new article of manufacture, a remote tuning device for radio receivers comprising a cabinet, a clock in said cabinet, the clock dial eing surrounded by a plurality of holes arranged in concentric circles, each hole having associated with it a normally open switch, a plurality of similarly' constructed pegs movably t mounted in said holes to close the switches for preselecting certain stations to be tuned in at certain intervals, and a set of keys projecting from said cabinet and manually operable to tune in a. desired station independently of the clock, and means for preventing operation of said manually operable keys so long as the normally open switches and the pegs are under the control of the clock.

14. In combination with a radio receiver set having a tuning element, an electric driving motor having a plurality of selectively operable control circuits with controls located at a point remote from said receiver, means controlled over each circuit and acting upon operation of the control point to energize said motor to move it a predetermined distance, means rendered effective by said motor upon movement of said predetermined distance for de-energizing the operating circuit of said motor, means for predetermining said distance and for making it different for each of said control circuits, a mechanical connection between said motor and said tuning element, and additional means rendered effective by the deenergization of the operating circuit of said motor for causing the disengagement of the connection between said motor and said tuning element whereby tuning of the radio receiver set may be effected.

15. In combination with a radio receiver set having a tuning element mounted on a rotatable shaft, an electric driving motor having a plurality of selectively operable control circuits with controls therefor located at a point remote from Said receiver, means controlled over each circuit and acting upon operation of said control points through suitable relays located in the circuit to energize said motor and move it a predetermined distance, means rendered effective by said motor upon movement of said predetermined distance for de-energizing the operating circuit of said motor, means for predetermining said distance and for making it different for each of said control circuits, a mechanical connection between said motor and said tuning element, and additional means rendered effective by the de-energi- Zation of the operating circuit of said motor for causing the connection between said motor and said tuning element to be disengaged whereby tuning at the radio receiver set may be effected.

16. In radio tuning apparatus, the combination of a rotary tuning shaft, an electric motor for selectively operating said shaft through predetermined fractions of a revolution, a plurality of disk members carried by and rotatable with said shaft, an insulated contact adjustably mounted on the periphery of each disk member, the several contacts being arranged in predetermined angular relation, manually operable means at a remote point and means under the control of said last means for closing a circuit to Aenergize the motor, and adjustable means in cooperative relation with each disk member i or causing the motor circuit to be selectively de-energized upon rotation of said disk members to predetermined positions at which their contacts and the adjustable means are in contacting relation.

ADOLPI-I A. THOMAS. 

